


thicker than water

by LillithShame



Series: Incestuous Fix-It Extravaganza [1]
Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Age Regression/De-Aging, Alternate Universe - Everyone Lives/Nobody Dies, Dubious Consent, Incest, Knotting, M/M, Monster sex, Sibling Incest, honestly i don't know how to tag most of this, more detailed content warnings at the beginning of each chapter
Language: English
Status: In-Progress
Published: 2019-08-16
Updated: 2019-08-16
Packaged: 2020-09-02 10:33:51
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Rape/Non-Con
Chapters: 1
Words: 2,610
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20274493
Author URL: https://archiveofourown.org/users/LillithShame/pseuds/LillithShame
Summary: There's only one thing in this world that Miklan wants... His baby brother back.





	thicker than water

**Author's Note:**

  * For [Iolite666](https://archiveofourown.org/users/Iolite666/gifts).

> I specifically made a fresh account just to post this and other similar content.  
Fic will contain explicit sexual content between brothers, including noncon/dubcon situations, (mental) age regression, and sex between a human and non-human monster; You've been warned. More detailed warnings will be added at the beginning of each chapter.  
(The fic itself is actually fairly romantic/consensual overall even despite all of that so if that's also a problem for you, be warned of that as well.)  
This first chapter is completely SFW with only mild depictions of violence, much less intense than in the actual source material.

“Professor?”

The only thing that made Byleth look up from the week’s lesson plan she had been going over rather than doing her usual ‘invite whatever student needed her attention into her room without so much as a glance upwards’ routine was the strange, almost strained quality of Ingrid’s voice. For someone who had been rightly told she had the emotional range of a paper mache mask for most of her life, Byleth didn’t have as hard a time as some would expect reading the emotions of others. And Ingrid sounded…

Well, concerned might have been a bit of an understatement.

“Just a moment.” Rather than summon her inside to talk while she continued with her work, Byleth gave her apparent distress the respect she felt it deserved and got up from her desk to open the door to her. What she found was Ingrid standing there with her typical level of controlled formality, but a distinct sense of anxiety humming in the air around her, and expressing itself in the way her eyes darted around occasionally like she was expecting a sudden attack. “What is it, Ingrid?”

“You… Haven’t seen Sylvain today, have you?” Her eyes darted back and forth again. Maybe it wasn’t enemies she was concerned with, so much as eyes and ears that were potentially unfriendly in  _ other _ ways…

Ingrid always seemed to be keeping an eye out for Sylvain, covering for him in situations like his constant womanizing, but despite the same basic principle Byleth could instantly tell that there was something quite different about this situation. The fact that Ingrid was clearly worried rather than annoyed, for one…

And the fact that she  _ hadn’t _ seen Sylvain since class the day before, which was exactly what she told Ingrid.

Her answer obviously wasn’t the one Ingrid wanted to hear, not that she expected it would be.

“I’m… Worried about him, Professor,” she said, shifting her weight from foot to foot anxiously. “Sylvain and his brother aren’t especially close, but… He’s been acting kind of weird ever since we found out about our mission this month. I’m worried about him. You don’t think he’d do something…  _ Drastic _ , do you?”

Byleth almost said ‘no’ by reflex, to console her, but when she took a moment to think about it she wasn’t quite certain. Sylvain was by no means as foolish as he liked to act, but she’d also seen him behaving strangely ever since they’d been told about his brother’s theft of his family’s Relic, and that once his hideout was located, it would be their job to reclaim it from him by force…

“Let’s go figure out who was the last person to see him,” she offered instead, because she didn’t have the answers Ingrid was looking for…

But someone would.

“Hello, Professor! Hello Ms. Ingrid! Nothing to report today!” The gatekeeper smiled brightly at the two of them, but his face fell into a worried frown. “Is something wrong? Anything I can do to help?”

“We’re looking for Sylain,” Byleth replied flatly, never one to beat around the bush.

“Have you seen him at all today?” Ingrid asked, fiddling with the hem of her uniform jacket, little signs of anxiety pouring out of her facade of collectedness like cracks in a dam that was about to burst.

Byleth was  _ very much _ hoping her favourite casual observer of the Monastery’s comings and goings would have an answer for her before the flood happened.

“Sylvain? Hm… Oh! Yes! I saw him just this morning, in fact!” the gatekeeper replied with his usual bright cheer. “He was heading into town, reading a letter and looking pretty troubled… Almost walked face first into a couple of people! Think he’s having some sort of girl trouble, maybe?”

Byleth and Ingrid shared a worried look— or what passed for one coming from Byleth, at least.

“Thank you,” Byleth said, ignoring the gatekeeper’s rhetorical question. “If you see him again, will you let him know we’re looking for him?”

“Sure thing, Professor!”

They left him to his enthusiastic duty, moving off to the side beyond the concealing curve of a wall to give themselves some privacy.

“I wish I could say Sylvain wouldn’t just wander off like that without telling someone, but…” Ingrid sighed and shook her head. “Honestly, the gatekeeper could very well be right. Still…”

“I don’t like the sound of it,” Byleth agreed, picking up her unfinished sentence. “Not considering the timing. You were the one who said he’s been acting strangely since we found out about his brother.”

“He didn’t mention any kind of upsetting letter or anything the last time I spoke with him, either,” Ingrid said. “What do you think we should do, Professor…?”

Ingrid looked to her almost pleadingly, asking for the confirmation she needed from an authority figure that yes, it was time to be worried.

Maybe it wasn’t the most appropriate response for a teacher (but then, no one had accused her of being a good teacher, and many people accused her of exactly the opposite) but the first thig out of her mouth then was, “We need to tell Dimitri.”

“The shopkeep told me he saw someone who matches Sylvain’s description earlier today, but he has no idea which way he went.”

“Hm… That does mean he passed through here, though. Thank you, Ashe.”

Telling Dimitri had turned, to no one’s surprise, into telling the rest of the class, rounding them up, and heading out to the town. Byleth was glad for the relative and somewhat surprising freedom afforded to the students, so long as she could come up with some kind of half-baked excuse as to why she was taking her entire class (minus one student) out of the Monastery.

Of course, she could have just told the truth when asked, but…

“Are you sure we shouldn’t tell the Knights about this? I mean, more numbers means faster searching, right? If Sylvain really is in some kind of trouble…”

“What, and get them all worked up only for us to find him in some poor unsatisfied farm girl’s hay pile?”

Annette’s suggestion of course sounded perfectly reasonable to everyone, but then, so did Felix’s callous reply. They really had no idea what had happened to Sylvain, and dragging the Knights into it without any further information wasn’t something Byleth wanted to do, particularly considering what she and Ingrid (and no doubt the rest of the class) were both fairly sure Sylvain was upset about in the first place…

She said nothing about the callousness of Felix’s brush off, nor did anyone else, even Annette. For how casual and calm his words were, no one could miss the tenseness of every muscle in Felix’s body, the furrow of his brow, the twitchiness of his hands and the way he didn’t seem to want his hand off his sword for too long.

If Ingrid was worried, then Felix had tipped over into downright  _ paranoid _ , and the longer they searched for Sylvain the more and more justified Byleth thought his reaction was.

Following the gatekeeper’s guidance, and after telling Dimitri about the situation (and subsequently the rest of the class), they’d left the Monastery and gone into town. Asking people around town if they’d seen Sylvain, they’d mostly gotten people saying they’d seen him but he hadn’t stopped to chat and they didn’t know where he was going, and a few pointing them in a vague general direction based on his wandering.

Well, maybe wandering wasn’t the right word. If what the same people said was to be believed (and Byleth had no reason not to believe them), Sylvain wasn’t so much wandering as // heading somewhere quite purposefully, albeit in something of a daze, though no one had any clues as to what that purpose might be…

The realization struck Byleth at that moment that they really didn’t have anywhere else to go, and as she looked around at her worried students she could tell they were all having the same thought. They’d made their way through the town and were more or less on its outskirts now, where the houses had more space between them and streets were becoming roads that would lead into fields if you want in one direction, and in the other…

The forest.

“Alright.” Dimitri’s voice cut through the fog of anxiety, although the way his arms were crossed and his hands tightened around his own biceps showed that he wasn’t immune to the feeling in the air. “We know Sylvain came this way, and even with a headstart, he couldn’t have gotten very far on foot… If he was even  _ trying _ to get very far. If we continue on, we’ll certainly find him, or some more concrete information on where he might be going and why…”

Dimitri slipped easily into the role of leader, unsurprisingly, and though he often handed the reins to Byleth she was happy to give them back to him while she occupied herself with more practical thoughts than raising morale.

Namely, that, if after all of this they  _ did _ find Sylvain between a farm girl’s milky thighs, she was going to strangle him— provided Ingrid and Felix didn’t get there first.

Sylvain wasn’t exactly a ‘trekking through the wilderness’ kind of guy, which he was pretty sure most people could tell just by looking at him. Of course, he didn’t usually have much of a choice these days, but at least on long marches during missions he could amuse himself by  _ enjoying _ the sight of the Professor leading the way (especially since she’d ditched her cape and started favouring an outfit more like the girls’ school uniforms, with a skirt so short he really couldn’t  _ help  _ but see it fly up with every acrobatic sword-swing she did) or Mercedes’ figure being hugged so much more nicely by her combat outfits than the stuff she usually wore, or just by annoying Ingrid as much as he could.

Now, though… Now it was just him, on a long walk through a forest on something that you’d have to be pretty generous to describe as a  _ path _ when it was really just mud with some cart tracks in it, with nothing for company but his own thoughts and that damned letter.

_ If you want the lance and don’t want your friends getting hurt, meet me in the woods outside of town. Come alone. _

It was a trap, of course. It wasn’t even trying very hard  _ not _ to be a trap, which was why it had included a threat so thinly veiled that if a woman used it as a skirt she’d be arrested for exposure. And it was the threat that had him slogging his way through a dark forest even knowing the rough map that had been included with the letter was leading him straight into an ambush somewhere along the way.

When Byleth had told them their mission would be hunting down Miklan and retrieving the Lance of Ruin, Sylvain could hardly believe it. Not because Miklan had stolen the lance; that he had no trouble believing. Miklan would do anything to spite their family, even steal a Relic he couldn’t even  _ use _ .

No, it was the fact that the Church was sending  _ his class _ to handle Miklan and a small army of outlaws instead of, say, the trained knights that hung around the place lead by a guy they called  _ the Blade Breaker _ .

The not-a-road got even less road like, and Sylvain was pretty sure the only thing fuelling him at that point was pure spite. He didn’t even know who he was angrier with; Miklan for stealing the lance in the first place, or the Archbishop for deciding a bunch of teenagers and their teacher would be enough to take out a seasoned bandit king and his men!

He had memories, pretty distinct ones, of Miklan’s axe cleaving a training dummy clean in half. He wasn’t about to let that happen to any of his friends, no matter how obvious a trap he had to walk into…

The “path” diverted sharply to the left, but the map he’d been helpfully provided told him to continue on in the same direction… Which meant right into the trees and the underbrush.

Fantastic. His day just kept getting better.

And maybe if he kept complaining about having to walk a lot and getting his clothes dirty and everything else he could think of, it would continue distracting him from the fact that he was walking straight towards his own death.

Another quarter of an hour walking, this time combined with dodging low tree branches trying to scratch his eyes out and tripping over protruding tree roots, he came to the end of the marked path on the map that he’d only been able to follow because someone had helpfully etched little markings into the trees along the way.

The trees opened up into a clearing— nothing to write home about, just a patch of mud with slightly fewer trees than everywhere else, but big enough that you could throw up a couple of tents and make yourself comfortable for the night. Which, judging by the trampled grass with muddy footprints everywhere and the unmistakeable remains of a campfire, was exactly what someone had done not too long ago…

“Miklan? I’m here, alone, like you said.”

It was stupid to so loudly and boldly announce himself, he knew that. But on the other hand it really wasn’t any stupider than anything else he was already doing. If he was walking into a death trap, they might as well get it over with nice and quick…

See, he had no doubts that once Miklan had him, he wouldn’t hurt his friends. Not because Miklan struck him as especially honourable, but because Miklan had no reason except for him to pick a fight with the Church and the Knights of Seiros in the first place. He couldn’t even  _ wield _ the Lance, what was the point of stealing it other than to piss off their father… And give him something to use against Sylvain?

“Come on out,” he said, gritting his teeth against how whiny he knew he sounded. Playing the spoiled airhead was all well and good, but it definitely wasn’t going to win him any points with his psychotic older brother. “I’ve been walking for hours and I don’t feel like playing games, okay? So why don’t you just—”

Sylvain cut himself off, not voluntarily, but because all of the wind was suddenly and violently knocked out of him by something hard and blunt striking him dead center in the back. With the slippery mud underfoot (and him not even in real armour, but still wearing his school uniform and less than practical shoes), he didn’t even manage to go to one knee; he ended up face down in the mud, struggling to breathe…

The silent was replaced with the mad shuffling of feet that he could see in the edges of his vision, and clipped, barked orders that the ringing in his ears made impossible to make out. Someone hauled him up to his knees by both arms, making his vision spin sickeningly, and he almost wished he’d left on a full stomach just so he could throw up on whoever was yanking him around—

Then, before he could even gather enough breath to start throwing some truly creative curses at his attackers, a rag that smelled sickeningly sweet and chemical was pressed up against his mouth and nose, forcing him to breathe it in or choke as the world spun, and spun…

And then went dark.


End file.
